Thanks for your response.

I can now compile and build an executable, but running it gives a pop-up saying (translated):

Can't find entry point of procedure FT_Get_BDF_Property in DLL C:\Program Files\Gtk-Runtime\bin\libfontcongif-1.dll.

When I run it via Eclipse it outputs to the console:

object.Exception@......\AppData\Roaming\dub\packages\gtk-d-3.6.5\gtk-d\generated\gtkd\gtkd\Loader.d(125): Library load failed (libgdk-3-0.dll): The specified module could not be found.